Switch actuator mechanism



Filed Sept. 3, 1959 III Q 4 w B 6 3 w ,A M r .91 3 8 2 x 6 M%% a 1M 1. 2, w 4% United States Patent 3,040,152 SWITCH ACTUATOR MECHANISM Richard L. Besemer, Reynoldsburg, Ohio, assignor to Robertshaw-Fulton Controls Company, Richmond, Va., a corporation of Delaware Filed Sept. 3, 1959, Ser. No. 837,918 3 Claims. (Cl. 200-172) This invention relates generally to switch actuator mechanisms and more particularly to mounting means for switch actuator levers.

In the past, switch actuator levers have been mounted on the switch casing by a pivotal construction or by mounting a bent end of the lever in a groove in the casing to form a resilient hinge. The pivotal mounting is unsatisfactory in that it requires an excessive number of parts. In the construction using the resilient hinge mounting, the actuating force on the lever must be of sufficient magnitude to overcome the bias of the resilient hinge and hence this construction would be undesirable in switches wherein it is important to use a very small actuating force.

It is an object of this invention to reduce the magnitude of the switch actuating force.

Another object of this invention is to wear on the switch actuator lever and thereby prolong the life of the switch actuating mechanism.

Another object of this invention is to construct a switch actuator mechanism with a minimum number of parts which will render it economical to manufacture and facilitate installation and repair.

In a preferred embodiment of the invention, the actuator lever is mounted on the exterior of the switch casing by means extending from one end of the lever through a slot in the switch casing into the interior thereof. A portion of the switch means is engageable with a fulcrum means within the casing when the other lever end is actuated relative to the casing whereby the lever rocks about the fulcrum means.

The above and other objects and features of this invention will appear more fully from a consideration of the following description taken in connection with the accompanying drawing wherein:

FIG. 1 is a plan view of a preferred embodiment of the invention;

FIG. 2 is a sectional view taken on line 11-11 of FIG. 1;

FIG. 3 is a bottom plan view of the embodiment shown in FIG. 1; and

lgIG. 4 is a sectional view taken on line IV-IV of F1 1.

Referring now more particularly to the drawing, the top wall of a switch casing 12 is provided adjacent one end with a transverse slot 14. A metallic reinforcement plate 16 is positioned adjacent the inner side 18 of top wall 10 and has a transverse slot 20 corresponding to slot 14. Slots 14 and 20 cooperate to define a slot 22 extending through switch casing 12 to the interior thereof.

Top Wall 10 also has a hollow boss 24 intermediate its ends defining a cylindrical bore 26 extending through switch casing 12. The wall of bore 26 slidably receives a cylindrical switch button 28 which is biased axially outwardly of switch casing 12 as is indicated at 30. The inner end 32 of switch button 28 has an annular flange portion 34 which engages the underside of boss 24 and limits the outward movement of button 28, the latter being of sufficient length to project slightly above the upper surface of boss 24. When switch casing 12 is completely assembled, the inner end 32 of switch button 28 is designed to be operatively engageable with the switch operating mechanism (not shown) contained in casing 12.

Means are provided for actuating switch button 28 axially within bore 26. To this end, a metallic switch actuator lever 36 is mounted on the exterior of top wall 10 so that a medial portion thereof is engageable by the projecting end 38 of switch button 28-. Actuator lever 36 may thus oppose the bias of switch button 28 to position the same.

A pair of fingers 40 extend from one end 42 of actuator lever 36 and at right angles thereto through slot 22 into the interior of switch casing 12. Fingers 40 have inner end portions 44 extending transversely of slot 22 to restrict the removal of fingers 40 therefrom. Each inner end portion 44 presents an arcuate edge 46 which faces a portion of the inner edge 48 of slot 20. In assembling the switch actuator mechanism, inner end portions 44 are bent into position after they have been inserted into slot 14 in switch casing 12 and slot 20 in reinforcement plate 16. Fingers 40 thus retain reinforcement plate 16 in its assembled position adjacent inner side 18.

The end 42 of actuator lever 36 also has a pair of ears 50 extending laterally thereof. Bars 50 overlie top wall 10 and are engageable therewith to restrict inward movement of fingers 40 and thereby serve to position the same. A pair of recesses 52 are formed in top wall 10 and are adapted to receive ears 50.

The other end 54 of actuator lever 36 is adapted to receive the application of an actuator force thereto as is indicated by the arrow 56 in FIG. 2. In its normal relaxed position wherein no actuator force is applied to end 54, actuator lever 36 rests on the outer end 38 of switch button 28 which projects from top wall 10 because of its outward bias. When an actuating force is applied to end 54 to move the same toward top wall 10, actuator lever 36 at first tends to pivot on switch button 28 and pulls the arcuate edges 46 of end portions 44 tightly against inner edge 48. Continued inward movement of end 54 will cause the actuator lever 36 to rock about inner edge 48 which acts as a fulcrum. As actuator lever 36 rocks inwardly about inner edge 48, switch button 28 is moved inwardly against the bias thereof.

It will thus be apparent that as a result of the rocking mounting for actuator lever 36, the only opposition to the actuator force 56 is the bias 30 of switch button 28 and there is no opposing force provided by actuator lever 36. Thus, as end 54 of actuator lever 36 is reciprocated, the switch button will be actuated into and out of switch casing 12 with a minimum actuating force. Also, the rocking action practically eliminates wear at the metalto-metal contact point between fingers 40 and plate 16 as there is no friction whereby the actuator mechanism will have a long life.

Although only one embodiment of this invention has been shown and described for purposes of illustration, the invention may be variously embodied and changes may be made in the construction and arrangement of parts without departing from the scope of the invention as defined by the appended claims.

I claim:

1. A switch actuator for a switch mechanism having an insulating casing provided with a substantially rectangular slot having an elongated end wall and a pair of opposite side walls, a switch operating plunger projecting from the casing adjacent the end wall of the slot, comprising a generally rectangular rigid lever adapted for overlying the plunger with a free end remote from the slot, said lever having the opposite end thereof extending substantially at a right angle to the plane of said lever, said opposite end having a pair of finger elements depending from the outer edges thereof and being reversely bent intermediate the ends, said reversely bent portions having arcuate surfaces forming bearing edges thereon, a reinforcement member positioned on the interior of said casing and having an aperture adapted for registry with the slot and providing an elongated end wall having an inner edge portion for operative engagement with said bearing edges, said engagement providing a fulcrum means for rocking movement of said lever relative to said end Wall and thereby operation of the plunger upon application of a force to said free end, said opposite end of said lever having a pair of oppositely disposed ears extending outwardly therefrom and adapted for operative engagement with the exterior of the casing for restricting movement of said fingers into the slot to thereby position said bearing edges in said operative engagement.

2. For use in combination with a switch mechanism having a casing and a switch operating plunger operatively mounted in said projecting outwardly through one Wall of said casing; an actuator assembly comprising a one piece lever member of sheet material having an elongate flat lever arm portion, a pair of spaced parallel fingers on said lever member projecting downwardly from the forward end of said arm portion, means defining an elongate slot through said one Wall of said casing adapted to receive said fingers with said fingers slideably engaged with the respective transverse end walls of said slot, said slot being located in spaced relationship to said plunger to locate said arm portion of said lever in overlying relationship with said plunger when said fingers are received within said slot, a lateral projection at the lower end of each finger inclined rearwardly and inwardly of said lever member into spaced underlying relationship with said arm portion, said projections extending transversely of said slot into underlying engagement with the inner surface of said one Wall of said casing when said fingers are received in said slot, a pair of cars integral with and projecting outwardly from said lever member at the upper ends of said fingers, and means defining an ear receiving recess in the outer surface of said one wall of said casing at each end of said slot.

3. A switch actuator assembly as defined in claim 2 further comprising a reinforcement plate having an elongate slot therein adapted to receive said fingers, said plate being retained upon said fingers in engagement with the inner wall of said casing by said lateral projections.

References Cited in the file of this patent UNITED STATES PATENTS 2,053,373 Money Sept. 8, 1936 2,743,331 Lauder et a1. Apr. 24, 1956 2,869,392 Muller Jan. 20, 1959 2,892,050 Fisher June 23, 1959 2,898,428 Holden Aug. 4, 1959 

